Audio encoders and in particular lossless audio encoders typically employ a FIR (Finite Impulse Response) prediction filter to reduce the entropy of an audio signal. Employing an IIR (Infinite Impulse Response) prediction filter may lead to improved prediction results and to reduced entropy of the prediction error signal. IIR prediction filters may e.g. be used in the so-called Dolby TrueHD lossless encoder. However, unlike FIR predictors it is typically difficult to derive optimal IIR prediction coefficients on a frame-by-frame basis that guarantees the stability of the predictor system (for the encoder) and its inverse system (for the decoder).
The present document addresses the above-mentioned technical problem. In particular, the present document describes methods for determining the coefficients of IIR-based prediction filters which lead to improved prediction results (i.e. which lead to a reduction of the entropy of the prediction error signal). The IIR prediction filters may be determined such that stability may be guaranteed. As such, the methods described in the present document enable the use of IIR-based prediction, thereby providing audio encoders (in particular lossless audio encoders) with improved coding gains.